Abstract

River floods can be very damaging. Since numerous human responses to floods are possible, the question arises: What is the organization of flood management that leads to the most efficient results? The dissertation first considers flooding and flood management in Germany. Based on that analysis, a theoretical, political-economy model of public flood defense is developed. The basic model is then extended to allow migration between upstream and downstream regions as well as between flood-prone areas and zones without risk. As different flood protection measures have quite different spatial characteristics, the distribution of responsibilities between the different actors is decisive for the overall performance of flood management. The distribution of public responsibilities among the different federal actors is crucial for two reasons. First, there are unidirectional upstream-downstream spillovers that raise the question whether decentralized or centralized provision of public goods is more efficient. Second, benefits from flood protection are concentrated to flood-prone areas near rivers. This concentration creates a natural heterogeneity of preferences for flood defense. These two aspects are also relevant for other issues in water management. Unidirectional spillovers and spatially heterogeneous preferences for public goods challenge the federal organization of flood defense. Following the lead of recent political-economy contributions to fiscal federalism, both aspects are investigated in a two region model with majority voting. Four different decision-making structures are compared: classical decentralization or centralization (based on jurisdictions containing voters both with and without preferences for the public good) and decentralized or centralized single issue authorities (whose jurisdictions, by definition, contain only high preference voters). Decentralized jurisdictions separate upstream and downstream voters, whereas a centralized jurisdiction comprises both groups. It turns out that centralized jurisdictions lead to a very low public good surplus and that either classical decentralization or decentralized single issue authorities achieve the best results under most conditions. The centralized provision of public goods is flawed because there is either an extreme over- or an extreme under-provision of the downstream public good. This can, however, be mitigated if there is a common standard for flood protection or if only the upstream provision of the public good is centralized. Whether or not these two solutions are beneficial depends on the magnitude of spillovers and also on the voting majorities in the two regions. Expanding the model to consider migration led to more complex results. First, citizens can migrate to flood-prone areas. Such migration flows can be induced by too large public flood defense, which is favored if citizens outside of flood-prone areas also finance the public good. Second, migration flow is also influenced by spillovers. The socially efficient population distribution is U-shaped with respect to spillovers. With symmetry assumptions, negative as well as positive unidirectional spillovers favour larger downstream populations. With myopic voters that neglect migration flow, this pattern is not achieved and the downstream population is large for positive spillovers and small for negative spillovers. Centralized jurisdictions are preferable to decentralized ones for smaller spillover effects if migration is possible. This argument is even stronger if voters take migration responses to the provision of public goods into account. The results shed light not only on the federal organization of flood management, but also on the institutional difficulties that arise from the current policy paradigm of the river basin approach to water management.